This disclosure relates generally to rescue hoists. More particularly, this disclosure relates to automatic testing of overload protection in rescue hoists.
Rescue hoists deploy and retrieve a cable from a cable drum to hoist persons or cargo. A motor and gear train cause the cable drum to rotate and to thus deploy or retrieve the cable. The gear train typically includes an overload clutch. The overload clutch provides overload protection to the rescue hoist, as the friction discs of the overload clutch are configured to slip at a predetermined load, which is typically about twice the rated capacity of the rescue hoist. The friction discs slipping disconnects the cable drum from other components of the drive train and from the motor, thereby allowing the cable drum to rotate and unspool the cable in response to the overload event. The overload clutch thus provides overload protection to the rescue hoist and to the object carrying the rescue hoist, such as a helicopter or other aircraft.